Pseudoaneurysmatic complication of an arteriovenous graft

Pseudoaneurysm is a rare complication of arteriovenous-grafts (AVGs) used in hemodialysis patients. Rupture and bleeding are the most common complications. In this case report, I present the case of a successful repair of an infected pseudoaneurysm that occurred at the AVG, its surgical ligation and the insertion of a new graft segment. Konstantina Triga ( ) Corresponding author: ktriga@gmail.com Triga K. How to cite this article: Pseudoaneurysmatic complication of an arteriovenous graft [version 1; referees: 1 approved, 1 2013, :228 (doi: ) approved with reservations, 1 not approved] F1000Research 2 10.12688/f1000research.2-228.v1 © 2013 Triga K. This is an open access article distributed under the terms of the , which permits Copyright: Creative Commons Attribution Licence unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Data associated with the article are available under the terms of the (CC0 1.0 Public domain dedication). Creative Commons Zero "No rights reserved" data waiver The author(s) declared that no grants were involved in supporting this work. Grant information: Competing interests: No competing interests were disclosed. 29 Oct 2013, :228 (doi: ) First published: 2 10.12688/f1000research.2-228.v1 Referee Status:


Introduction
Improvements in hemodialysis techniques have led to an extended life expectancy such that the number of patients with end-stage renal disease is increasing 1 .Complications regarding vascular access are the main causes of hospitalization in dialysis patients 2,3 .Nowadays, it is recognised that autologous arteriovenous fistulas (AVF) lead to better long-term results when compared to other possible vascular accesses, including polytetrafluoroethylene (PTFE) grafts [4][5][6] .Although the creation of an AVF is a common practice, many patients require secondary or tertiary access procedures.Indeed, an important complication of AVFs is aneurismal dilatation of the venous end which can rupture and cause hemorrhages that can even be fatal 7 .
Pseudoaneurysm is also a relatively rare 1 (2% to 10%) complication of dialysis access graft 1 and comes from repeated needle punctures.An arteriovenous bridge graft, usually with PTFE, continues to be a reasonable alternative form of hemodialysis access 1,8 .The creation and maintenance of hemodialysis access occupies a significant portion of most vascular and general surgery practices 9 .

Presentation of the case
A 78-year-old Caucasian Greek man presented with a well defined round region of 2-3 cm diameter, with discoloration, swelling and pain in the arteriovenous graft anastomosis in his left upper extremity.He had been on hemodialysis for 6 years as a result of end-stage renal disease.Hemodialysis was originally initiated with an arteriovenous cimino fistula in his left arm, which provided low blood supply and was thus considered non-functional.The access was switched to a new arterio-venous fistula in his right upper arm, which thrombosed after 3 years.Eventually an arteriovenous graft was placed between the brachial artery and axillary vein in his left upper arm.After two years, upon physical examination, a pulsatile mass was found in the middle of the arteriovenous graft anastomosis.A murmur was detected on auscultation.The size of the pseudoaneurysm was approximately 2 × 3 cm.Within a month's time, he presented with swelling and discolouration of the aneurismatic mass which had developed a purulent outflow.The patient was referred to surgeons who performed a longitudinal incision and explored the pseudoaneurysm sac.

Diagnosis and therapeutic intervention
An infection was confirmed after taking cultures when the aneurismal sac was opened.There was a destructed segment of about 6 cm in length at the initial AVG.The defect in the graft was repaired with the interposition of a second PTFE graft that was placed next to the initial graft and was anastomosed in an end-to-side fashion by performing a bypass procedure in the same section.The surgical procedure was successful and the patient was discharged without any complications on the same day.The patient continued hemodialysis sessions after this for three years without any complications.

Discussion
The progressive increase in the number of hemodialysis patients makes vascular access creation a common procedure.There are three different choices for hemodialysis access, an AVF, AVG and a central catheter.The brachiocephalic AVF in the forearm should be the first choice 1 .However, some patients lack available veins for AVF creation or have unsuitable superficial veins due to their use for repeated arteriovenous fistula procedures.In these cases, upon the exhaustion of all autologous AVF possibilities, a PTFE prosthetic graft becomes an alternative necessity in order to bridge arteries and veins.It is usually placed as an arm or forearm loop graft or even as an axillary-brachial bypass graft.A successful procedure requires adequate blood flow, and, therefore, the rotation or angulation of the prosthesis needs to be avoided.
Common complications of a vascular access include thrombosis, infection, venous hypertension, and aneurysmal degeneration 10,11 .Thrombosis is the most common complication in 90% of AVFs 12 .The use of antiplatelet agents, marcumar or other agents may reduce the risk of thrombosis 13 , but there is a risk of bleeding and further studies need to prove this hypothesis.
True aneurysms are most likely to occur in native AVFs, compared with AVGs where a pseudoaneurysm may occur.The indications for surgical intervention of venous aneurysms are progressively increasing size, thrombosis or an open skin lesion 14 .
Focal aneurysms can be managed either with manual ligation, embolization and thrombin injection under ultrasonographic guidance 15 , interposition, replacement with vein or a prosthesis, or resection and imbrication.PTFE grafts can also lead to bleeding, dilatation, infection, pseudoaneurysm, seroma, steal, swelling, stenosis or thrombosis 1,8 .Duplex scans can define the exact nature and extension of the aneurysm 1 .
The development of a graft-related pseudoaneurysm is multifactorial 16 .Repeated canulations may cause disruption and fragmentation of the PTFE graft material 16,17 .Further, progressive enlargement of a pseudoaneurysm can lead to the breakdown of the overlying skin, spontaneous bleeding, and rupture 16 .Surgical repair is recommended 16,18 .The main treatment includes ligation and resection of the graft followed by insertion of a new interposition graft segment 16,19 .
In this case study, the aneurysm was infected to such an extent that it caused the patient's arteriovenous graft to rupture.The surgeons repaired the graft with the interposition of a second PTFE AVG placed right next to the initial one.They performed a bypass procedure in the same section by anastomosing the second graft in an end-to-side fashion.After completing the resection procedure of the AVF aneurysm, the patient's new AVG was canulated without any complications.Our patient was therefore satisfied with the outcome of the surgery.
Concluding, AV dialysis accesses are associated with multiple complications 20 .The traditional repair of hemodialysis graft pseudoaneurysms requires the surgical replacement of the segment that involves the PTFE graft material or autogenous vein 16,19,21 .Careful attention to technical detail is required, such as focusing on patients with development of arm swelling or discomfort after surgical access placement or hemodialysis sessions; decreased flow rates during dialysis, suspected of having a pseudoaneurysm;

Rajesh Agarwala
Florida Kidney and Hypertension Specialists, Orange City, FL, USA This case report is well written and will be helpful to practitioners.

Major concerns:
The case report needs to add a few additional details, especially: A graphical representation of the blood flow over certain time periods.The gauge of the needle used for this patient Access recirculation, if any.

KT/V
The ratio of AVF fistula vs AVG vs catheter in the institute.Ultrasonography pictures of pre and post procedures.The time duration between the placement of AVG and cannulation.Details of the organism(s) detected from the culture.These are all the educational points which will help the practitioners at the outset.
The case reports' stress is currently on the procedure, which is not unique.Instead, as this article is addressed to the nephrology community, I would suggest that the stress should be changed so as to lean more towards the event that lead to the pseudo-aneurysm.
No competing interests were disclosed.

Competing Interests:
I have read this submission.I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.

Major comments:
The current status of the manuscript provides insufficient details to be useful for other practitioners.Additionally, important details of diagnostic tests are missing.However, most importantly the discussion does not demonstrate why the finding is important and why it should be relevant for the future treatment of infected pseudoaneurysms.Thus, it is not clear what the key message of the case report is.Is it an example of a specific surgical procedure?Is it that a new prosthetic material was placed in an infectious site or is there another aspect?In any case, the author should include a key message in this case presentation which has importance for practitioners who care for patients on hemodialysis.Therefore, the manuscript needs major revision to be indexed.

References
Some statements are not sufficiently supported by the cited references.Some examples are listed: To support the statement "Improvements in hemodialysis techniques have led to an extended life ", expectancy such that the number of patients with end-stage renal disease is increasing epidemiological and outcome data is needed.The cited reference, a case report in which an anastomotic pseudoaneurysm developed in a patient during the early period of hemodialysis treatment, is insufficient to confirm the author`s statement.Also, to support the statement "Complications regarding vascular access are the main causes of the cited reference 3 is insufficient, since the paper exclusively hospitalization in dialysis patients" describes the outcome of Thomas shunts.To support this statement the author should search for confirming epidemiological data."The progressive increase in the number of hemodialysis patients makes vascular access creation a common procedure.There are three different choices for hemodialysis access, an AVF, AVG ." These and a central catheter.The brachiocephalic AVF in the forearm should be the first choice statements are not sufficiently supported by the cited reference.Epidemiological and outcome data are needed as reference.

Introduction and Discussion
The introduction and discussion should be more focused on the case presentation.Especially the second and third paragraph of the introduction, which could be more focused and serve as a background on "pseudoaneurysm in arteriovenous-grafts (AVGs)".
The last two sentences of the third paragraph add nothing to the subject of the manuscript.Further, 1.

2.
The last two sentences of the third paragraph add nothing to the subject of the manuscript.Further, most of the first three paragraphs of the discussion can be omitted and the discussion can be substantially shortened.Some examples are listed: "The use of antiplatelet agents, marcoumar or other agents may reduce the risk of thrombosis, but there is a risk of bleeding and further studies need to prove this hypothesis.""The indications for surgical intervention of venous aneurysms are progressively increasing size, thrombosis or an open skin lesion." Presentation of the case " ."The second part He had been on hemodialysis for 6 years as a result of end-stage renal disease of this sentence is redundant; ESRD is virtually always the reason to be on chronic hemodialysis.The beginning and end of the presentation are also redundant.The author should be more stringent in the case presentation.Further, it would be of interest to know whether there was an increase in systemic inflammatory markers and whether blood cultures were taken.In the discussion, the author writes: " In this case study, the aneurysm was infected to such an ." Could the author explain what extent that it caused the patient's arteriovenous graft to rupture exactly happened?Was a rupture of the graft noted?If yes, the author should add this to the case presentation.Were there risk factors for an infection?Does the author have any information about the underlying kidney disease and the metabolic situation, e.g.diabetes mellitus, cardiovascular risk factors and so on?
Diagnosis and therapeutic intervention " ."It would An infection was confirmed after taking cultures when the aneurismal sac was opened be of interest to know the result of a tissue culture.The information about the antibiotic therapy, type of antibiotics given and duration is missing.

Further remarks
I suggest rephrasing the term " ". alternative necessity How would you define " " in patients on hemodialysis?venous hypertension No competing interests were disclosed.

Competing Interests:
We have read this submission.We believe that we have an appropriate level of expertise to state that we do not consider it to be of an acceptable scientific standard, for reasons outlined above.management strategy is not novel however there is little reported in the literature on this subject.The article would benefit from pre and post procedure pictures.It would also be useful to hear about other case experiences in the unit that have long term outcomes.
Overall this case report is useful for other practitioners as it promotes monitoring/referral and highlights a management strategy for pseudoaneurysms.
No competing interests were disclosed.

Competing Interests:
I have read this submission.I believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard.
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